U.S. patent number 10,421,872 [Application Number 15/260,350] was granted by the patent office on 2019-09-24 for stain resistant coating composition.
This patent grant is currently assigned to The Sherwin-Williams Company. The grantee listed for this patent is The Sherwin-Williams Company. Invention is credited to Richard R Chamberlain, Philip J Ruhoff, Tom Wendland.
United States Patent |
10,421,872 |
Wendland , et al. |
September 24, 2019 |
Stain resistant coating composition
Abstract
The invention relates to acrylic emulsion comprising between 0.1
and 10% of at least one fluoromonomer, at least one polymerizable
phosphate functional monomer, and at least one wet adhesion
monomer. The combination of the fluoromonomer with a polymerizable
phosphate functional monomer and wet adhesion adhesion monomer act
together to greatly improve the stain resistance of the acrylic
emulsion.
Inventors: |
Wendland; Tom (Strongsville,
OH), Ruhoff; Philip J (Shaker Heights, OH), Chamberlain;
Richard R (Solon, OH) |
Applicant: |
Name |
City |
State |
Country |
Type |
The Sherwin-Williams Company |
Cleveland |
OH |
US |
|
|
Assignee: |
The Sherwin-Williams Company
(Cleveland, OH)
|
Family
ID: |
67988516 |
Appl.
No.: |
15/260,350 |
Filed: |
September 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62215969 |
Sep 9, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09D
5/022 (20130101); C09D 133/062 (20130101); C09D
5/1668 (20130101) |
Current International
Class: |
C09D
5/16 (20060101); C09D 133/06 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mulcahy; Peter D.
Attorney, Agent or Firm: Tsang; Vivien Y. Sherwin; Daniel A.
Ward; Daniel S.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional application
No. 62/215,969 filed on Sep. 9, 2015, the entirety of which is
hereby incorporated by reference.
Claims
What is claimed is:
1. A stain resistant latex emulsion composition comprising: (a)
0-60 weight percent of a styrene-based monomer, (b) 10 to 90 weight
percent of one or more (meth)acrylic monomers; (c) 0-60 weight
percent of a vinyl-based monomer; (d) 0.5 to 10 weight percent of,
chlorotrifluoroethylene or a fluorine monomer having a general
chemical structure of: CH2=CR--C(O)O(CH.sub.2).sub.n--R.sub.f
wherein R is hydrogen or methyl, .sub.n is an integer in the range
of from 0-20, and R.sub.f is a fluoroalkyl group having in the
range of 1 to 20 carbon atoms; (e) 0.1 to 5% by weight, based on
total monomer weight, of a polymerizable phosphate-functional
monomer; (f) 0.1 to 8% by weight of a wet adhesion monomer; all
based on the total weight of monomers.
2. The latex emulsion composition of claim 1, wherein the
fluorine-containing unsaturated monomer is selected from the group
consisting of 2,2,2-trifluoroethyl (meth)acrylate, perfluoromethyl
ethyl (meth)acrylate, perfluoroethyl ethyl methacrylate,
perfluorobutyl ethyl (meth)acrylate, perfluoropentyl ethyl
(meth)acrylate, perfluorohexyl ethyl (meth)acrylate, perfluorooctyl
ethyl (meth)acrylate, perfluorodecyl ethyl (meth)acrylate,
perfluorolauryl ethyl (meth) acrylate, perfluorostearyl ethyl
(meth)acrylate or combinations thereof.
3. The latex emulsion composition of claim 1, wherein the
polymerizable phosphate-functional monomer is selected from the
group consisting of allyl phosphate, mono- or diphosphate of
bis(hydroxy-methyl) fumarate or itaconate, derivatives of
(meth)acrylic acid phosphate esters, phosphonate functional
monomers, 1,2-ethylenically unsaturated (hydroxy)phosphinylalkyl
(meth)acrylate monomers, dihydrogen phosphate monomers,
2-phosphoethyl (meth)acrylate, 2-phosphopropyl (meth)acrylate,
3-phosphopropyl (meth)acrylate, 3-phospho-2-hydroxypropyl
(meth)acrylate.
4. The latex emulsion composition of claim 1, wherein the
polymerizable phosphate monomer is selected from the group
consisting of: (a) dihydrogen phosphate-functional monomers, or (b)
one or more phosphate monomers having at least one diester group;
or (c) one or more phosphonate monomers, or (d) ethylenically
unsaturated (hydroxy) phosphinyl alkyl (meth)acrylate monomers; or
(e) phosphoalkyl (meth)acrylates; or (f) phosphoalkyloxy
(meth)acrylates, where (meth)acrylate designates methacrylate or
acrylate; or a combination thereof.
5. The latex emulsion of claim 4, wherein the phosphonate monomer
is selected from the group consisting of mono or bis-(hydrocarbyl
or halohydrocarbyl)vinyl or allylphosphonates.
6. The latex emulsion of claim 4, wherein the ethylenically
unsaturated (hydroxy) phosphinyl alkyl (meth)acrylate monomer is
(hydroxy)phosphinylmethyl methacrylate.
7. The latex emulsion of claim 4, wherein the phosphoalkyl
(meth)acrylate monomer is selected from the group consisting of:
2-phosphoethyl (meth)acrylate, 2-phosphopropyl (meth)acrylate,
3-phosphopropyl (meth)acrylate, and 3-phospho-2-hydroxypropyl
(meth)acrylate.
8. The latex emulsion of claim 4, wherein the phosphoalkyloxy
(meth)acrylate monomer is selected from the group consisting of:
phospho-ethylene glycol (meth)acrylate, phosphodi-ethylene glycol
(meth)acrylate, phosphotriethylene glycol (meth)acrylate,
phosphopropylene glycol (meth)acrylate, phosphodipropylene glycol
(meth)acrylate, phosphotri-propylene glycol (meth)acrylate where
(meth)acrylate designates methacrylate or acrylate.
9. The latex emulsion composition of claim 1, wherein the wet
adhesion monomer is selected from the group consisting of
ethylenically unsaturated amino-, urea- and ureido-functionalized
monomers.
10. The latex emulsion of claim 4, wherein the phosphonate monomer
is a vinyl phosphonate monomer or allyl phosphonate monomer.
11. The latex emulsion of claim 4, wherein the phosphonate monomer
is selected from the group consisting of mono(ethyl)vinyl acid
phosphonate, mono(butyl)vinyl acid phosphonate, mono(octyl)vinyl
acid phosphonate, mono(cyclohexyl)vinyl acid phosphonate,
mono(phenyl)vinyl acid phosphonate, mono(benzyl)vinyl acid
phosphonate, mono(omega-chloroethyl)vinyl acid phosphonate,
mono(omega-chlorooctyl) vinyl acid phosphonate, bis (ethyl) vinyl
phosphonate, bis(butyl) vinyl phosphonate, bis (benzyl) vinyl
phosphonate, bis(omega-chloroethyl)vinyl phosphonate,
bis(omegachlorobutyl)vinyl phosphonate, bis(omega-chloroethyl)
allyl phosphonate, bis(benzyl)allyl phosphonate and bis(cyclohexyl)
allyl phosphonate.
12. The latex emulsion of claim 1, wherein the wet adhesion monomer
is selected from the group consisting of dimethylaminoethyl
acrylate and methacrylate, dimethylaminopropyl acrylate and
methacrylate, 3-dimethylamino-2,2-dimethylpropyl-1-acrylate and
methacrylate, 2-N-morpholinoethyl acrylate and methacrylate,
2-N-piperidinoethyl acrylate and methacrylate,
N-(3-dimethylaminopropyl) acrylamide and methacrylamide,
N-(3-dimethylamino-2, 2-dimethylpropyl) acrylamide and
methacrylamide, N-dimethylaminomethyl acrylamide and
methacrylamide, N-dimethylaminomethyl acrylamide and
methacrylamide, N-(4-morpholino-methyl) acrylamide and
methacrylamide, vinylimidazole, vinylpyrrolidone,
N-(2-methacryloyloxyethyl) ethylene urea,
N-(2-methacryloxyacetamidoethyl)-N,N'-ethyleneurea, allylalkyl
ethylene urea, N-methacrylamidomethyl urea, N-methacryoyl urea,
2-(l-imidazolyl) ethyl methacrylate, N-(methacrylamido)ethyl
ethylene urea and allyl ureido monomer.
Description
BACKGROUND
Stain resistance, especially liquid stain repellency, is one of the
key performance requirements for coating films. Stain resistance
including resistance to being wetted by liquid stain, resistance to
being adhered by stains, and/or ease of stain removal.
Stain resistance is achievable by the appropriate selection of
binders and additives in a coating formulation. The latex paints of
this invention can produce films which exhibit outstanding
stain-resistance and washability to both surface and penetrating
types of stains. The binder resins, in the practice of this
invention, are the copolymerization products of a mixture of
comonomers and which comprises a fluorine-containing unsaturated
monomer, and a polymerizable phosphate functional monomer and a wet
adhesion monomer.
DESCRIPTION OF THE INVENTION
The emulsion polymers used in formulating the latex paints for this
invention are all-acrylic copolymers comprising alkyl esters of
acrylic and methacrylic acid; or they are vinyl-acrylic polymers
comprising vinyl-containing monomers; or styrene-acrylic polymers
comprising alkyl esters of acrylic and methacrylic acid and styrene
or C.sub.1-C.sub.4-substituted styrene. The procedures used to
prepare the emulsions are well known in the art and generally
involve admixing under rapid stirring the comonomer charge with
water, surfactants or emulsifying agent, a polymerization initiator
or catalyst, and, in most cases, a protective colloid-forming
substance. The mixture is then heated to polymerization temperature
for the time required to substantially complete the emulsion
polymer formation. Many variations of the general preparative
procedure are used to obtain, for example, lower viscosity, high
solids content, improved freeze-thaw stability, etc.
As used herein, the expression "all acrylic copolymer" shall mean
copolymers derived from the copolymerization of esters derived from
the reaction of monohydric alcohols with acrylic acid or lower
alkyl-substituted acrylic acid, optionally, together with minor
amounts of other comonomers. Polymers can also include
multifunctional acrylates. The expression "multifunctional
acrylate" shall be understood herein to mean the esters derived
from the reaction of a polyhydric alcohol with acrylic acid and/or
lower alkyl-substituted acrylic acid, there being at least two
hydroxyl groups of the alcohol esterified with the aforesaid
acids.
In addition to the aforesaid acrylate and alkyl acrylate
comonomers, the monomer charge may include relatively small amounts
of one or more copolymerizable modifiers such as acrylic acid or
lower alkyl-substituted acrylic acid, e.g., methacrylic acid (to
introduce cross-linkable pendant carboxylic groups into the
copolymer backbone), hydroxyalkyl esters of acrylic acid or lower
alkyl-substituted acrylic acid such as 2-hydroxyethyl acrylate,
2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, etc. (to
introduce cross-linkable pendant hydroxyl groups into the copolymer
backbone), and an acrylic acid amide or lower alkyl-substituted
acrylic acid amide such as hydroxymethylene diacetone acrylamide,
or diacetone acrylamide (DAAM) with adipic acid dihydrazide (ADH)
crosslinking agent. Such comonomers can be included in the charge
at up to about 20%, and preferably from about 1% to about 5% of the
weight of said charge.
Also suitable are ethylenically unsaturated monomers such as
styrenated monomers, or vinyl esters, can be used as co-monomers.
Examples of (meth)acrylates include various (C.sub.1-C.sub.20)
alkyl or (C.sub.3-C.sub.20) alkenyl esters of (meth)acrylic acid;
for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl
(meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate,
isobutyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl
(meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate,
stearyl (meth)acrylate, .alpha.-chloroethyl (meth)acrylate,
cyclohexyl (meth)acrylate, phenyl (meth)acrylate, methoxyethyl
(meth)acrylate, ethoxyethyl (meth)acrylate, methoxypropyl
(meth)acrylate, ethoxypropyl (meth)acrylate lauryl acrylate, methyl
methacrylate, butyl methacrylate, ethyl methacrylate, isodecyl
methacrylate, and lauryl methacrylate. The expression (meth)acrylic
acid is intended to serve as a generic expression embracing both
acrylic and methacrylic acid. Similarly, the expression
(meth)acrylate is intended as a generic expression embracing both
acrylic acid and methacrylic acid esters. Examples of styrenated
monomers include styrene, alkylstyrenes (e.g.,
.alpha.-ethylstyrene, .alpha.-methylstyrene, vinyl toluene,
2,4-dimethylstyrene, 4-tert-butylstyrene, and the like), and
halostyrenes (e.g., .alpha.-bromostyrene, 2,6-dichlorostyrene, and
the like). Examples of vinyl esters include vinyl carboxylate alkyl
ethers (e.g., vinyl acetate, vinyl propionate, vinyl butyrates,
vinyl benzoates, vinyl esters of versatic acid or 2-ethylhexanoic
acid (commercially available under the tradename VeoVa.TM. from
Hexion Inc.), halo-substituted versions thereof such as vinyl
chloroacetate, and the like. Other ethylenically unsaturated
monomers that can be used as co-monomers include carboxylic
group-containing of monomers, hydroxyl group-containing monomers,
amide group-containing monomers, and amino group-containing
monomers.
Multifunctional acrylate polymerization promoters can be used that
are copolymerizable with the acrylate comonomers (and other
comonomers, if present) and thus constitute part of the comonomer
charge. The preferred promoters are esters of aliphatic and
cycloaliphatic polyols and acrylic and/or methacrylic acid.
The alkyl acrylate comonomers which are copolymerized herein are
preferably selected from esters derived from the reaction of a
lower alkanol with acrylic acid or methacrylic acid, examples of
which are: methyl acrylate, ethyl acrylate, propyl acrylate,
n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, methyl
methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl
methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, and
the like. Mixtures of an alkyl acrylate and alkyl methacrylate are
preferred, and of said mixtures, a combination of 2-ethylhexyl
acrylate and methyl methacrylate is especially preferred. The
2-ethylhexyl acrylate is generally present at from about 30% to
about 60%, and preferably from about 40% to about 60%, of the
weight of the total comonomer charge. The methyl methacrylate is
suitably employed at a level of from about 20% to about 60%, and
preferably from about 30% to about 50%, of the weight of the total
comonomer.
In accordance with this invention, a fluoromonomer, such as a
fluorine-containing unsaturated monomer, is used, which can be
selected from one or more of the following combination of monomers:
chlorotrifluoroethylene or a fluorine-containing monomer having the
structure (I): CH2=CR--C(O)O(CH2)n-R.sub.f FORMULA (I)
Wherein R is hydrogen or methyl, n is an integer in the range of
from 0-20, and R.sub.f is a fluoroalkyl group having in the range
of 1 to 20 carbon atoms. Examples of suitable fluoromonomers
according to formula (I) can include, for example,
2,2,2-trifluoroethyl (meth)acrylate, perfluoromethylethyl
(meth)acrylate, perfluoroethylethyl (meth)acrylate,
perfluorobutylethyl (meth)acrylate, perfluoropentylethyl
(meth)acrylate, perfluorohexylethyl (meth)acrylate,
perfluorooctylethyl (meth)acrylate, perfluorodecylethyl
(meth)acrylate, perfluorolaurylethyl (meth)acrylate,
perfluorostearylethyl (meth)acrylate, heptafluorobutyl
(meth)acrylate, octafluoropentyl (meth)acrylate, hexafluorobutyl
(meth)acrylate or combinations thereof. For example, trifluoroethyl
methacrylate (tradename FLUORESTER) is commercially available from
Tosoh Corporation, and octafluoropentyl (meth)acrylate (tradename
8-FM) is commercially available from San Ester Corp. The
fluoromonomers are generally used herein at from about 0.1% to
about 10.0%, preferably about 0.5% to about 5%, of the weight of
the total comonomer charge. Levels of fluoromonomers greater or
lesser than this can also be used to good effect depending upon the
nature of the charge and the particular reaction conditions
employed.
The polymerizable phosphate-functional monomer employed in
accordance with this invention can be selected from the group
consisting of: (a) dihydrogen phosphate-functional monomers, or (b)
one or more phosphate monomers having at least one diester group;
or (c) one or more phosphonate monomers, such as a vinyl or allyl
phosphonate; or (d) ethylenically unsaturated (hydroxy) phosphinyl
alkyl (meth)acrylate monomers; or (e) phosphoalkyl (meth)acrylates;
or (f) phosphoalkyloxy (meth)acrylates, where (meth)acrylate
designates methacrylate or acrylate; or a combination thereof. The
dihydrogen phosphate-functional monomers can be dihydrogen
phosphate esters of an alcohol in which the alcohol also contains a
polymerizable vinyl or olefinic group, such as allyl phosphate,
mono- or diphosphate of bis(hydroxy-methyl) fumarate or itaconate,
derivatives of (meth)acrylic acid esters, such as, for example,
phosphates of hydroxyalkyl(meth)acrylates including 2-hydroxyethyl
(meth)acrylate, 3-hydroxypropyl (meth)acrylates, and the like.
Commercial examples are the phosphate methacrylates SIPOMER.TM.
PAM-100, SIPOMER.TM. PAM-200, and SIPOMER.TM. PAM-4000 and the
acrylate, SIPOMER.TM. PAM-300, available from Solvay Inc. Other
suitable phosphate-functional monomers are phosphonate functional
monomers, disclosed in WO 99/25780 A1, and include vinyl phosphonic
acid, allyl phosphonic acid, 2-acrylamido-2-methylpropanephosphonic
acid, .alpha.-phosphonostyrene,
2-methylacrylamido-2-methylpropanephosphonic acid, mono or
bis-(hydrocarbyl or halohydrocarbyl)vinyl or allylphosphonates such
as mono(ethyl)vinyl acid phosphonate, mono(butyl)vinyl acid
phosphonate, mono(octyl)vinyl acid phosphonate,
mono(cyclohexyl)vinyl acid phosphonate, mono(phenyl)vinyl acid
phosphonate, mono(benzyl)vinyl acid phosphonate,
mono(omega-chloroethyl)vinyl acid phosphonate,
mono(omega-chlorooctyl) vinyl acid phosphonate, bis (ethyl) vinyl
phosphonate, bis(butyl) vinyl phosphonate, bis (benzyl) vinyl
phosphonate, bis(omega-chloroethyl)vinyl phosphonate,
bis(omegachlorobutyl)vinyl phosphonate, bis(omega-chloroethyl)
allyl phosphonate, bis(benzyl)allyl phosphonate and bis(cyclohexyl)
allyl phosphonate.
Further suitable phosphorus functional monomers are
1,2-ethylenically unsaturated (hydroxy)phosphinylalkyl
(meth)acrylate monomers, disclosed in U.S. Pat. No. 4,733,005, and
include (hydroxy)phosphinylmethyl methacrylate. Preferred
phosphate-functional monomers are dihydrogen phosphate monomers,
which include 2-phosphoethyl (meth)acrylate, 2-phosphopropyl
(meth)acrylate, 3-phosphopropyl (meth)acrylate, and
3-phospho-2-hydroxypropyl (meth)acrylate. Preferred are
2-phosphoethyl (meth)acrylate, 2-phosphopropyl (meth)acrylate,
3-phosphopropyl (meth)acrylate, 3-phospho-2-hydroxypropyl
(meth)acrylate, SIPOMER.TM. PAM-100, Harcryl 1228-HEMA Phosphate
monomer, and SIPOMER.TM. PAM-200. Preferably, the polymerizable
phosphate-functional monomer can be selected from one or more of a
combination of monomers and employed at levels of from about 0.1%
to about 5%, and in certain embodiments, up to 3%, of the weight of
total monomers present.
Ethylenically unsaturated phosphorus containing monomers can
include, but are not limited to, phosphoalkyl (meth)acrylates such
as phosphoethyl (meth)acrylate, phosphopropyl (meth)acrylate, and
phosphobutyl (meth)acrylate where (meth)acrylate designates
methacrylate or acrylate; phosphoalkoxy (meth)acrylates such as
phospho-ethylene glycol (meth)acrylate, phosphodi-ethylene glycol
(meth)acrylate, phosphotriethylene glycol (meth)acrylate,
phosphopropylene glycol (meth)acrylate, phosphodipropylene glycol
(meth)acrylate, phosphotri-propylene glycol (meth)acrylate where
(meth)acrylate designates methacrylate or acrylate; phosphoalkyl
(meth)acrylamides such as phosphoethyl (meth)acrylamide,
phosphopropyl (meth)acrylamide where (meth)acrylamide designates
methacrylamide or acrylamide; phosphoalkyl crotonates, phosphoalkyl
maleates, phosphoalkyl fumarates, phosphodialkyl (meth)acrylates,
phosphodialkyl crotonates, vinyl phosphates and (meth) allyl
phosphate. Preferred is selected from phosphoalkyl (meth)acrylates
or phosphoalkoxy(meth)acrylates, or the salts thereof, especially,
phosphoethyl methacrylate. It is also contemplated that the
copolymerized ethylenically unsaturated phosphorus containing
monomer may be formed after the polymerization of at least one
ethylenically unsaturated nonionic monomer and a phosphorus-capable
precursor monomer. A phosphorus-capable precursor monomer is a
monomer that has a reactive group that is capable, after
polymerization, of reacting with a phosphorus-containing compound
to yield a phosphorus-containing functional group attached to the
polymer. For example, a polymer containing, as a polymerized unit,
hydroxyethyl methacrylate which may then be reacted, as is well
known in the art, to form, for example, phosphoethyl methacrylate.
Similarly, for example, a polymerized carboxylic acid unit may then
be reacted, as is well known in the art, with an epoxy phosphate or
an amino phosphate.
In order to enhance the washability and wet adhesion properties of
the ultimate final latex coating, the monomer composition comprises
at least one wet adhesion monomer, or a combination of wet adhesion
monomers. These monomers are well known in the art and include
ethylenically unsaturated amino-, urea- and ureido-functionalized
monomers such as dimethylaminoethyl acrylate and methacrylate,
dimethylaminopropyl acrylate and methacrylate,
3-dimethylamino-2,2-dimethylpropyl-1-acrylate and methacrylate,
2-N-morpholinoethyl acrylate and methacrylate, 2-N-piperidinoethyl
acrylate and methacrylate, N-(3-dimethylaminopropyl) acrylamide and
methacrylamide, N-(3-dimethylamino-2, 2-dimethylpropyl) acrylamide
and methacrylamide, N-dimethylaminomethyl acrylamide and
methacrylamide, N-dimethylaminomethyl acrylamide and
methacrylamide, N-(4-morpholino-methyl) acrylamide and
methacrylamide, vinylimidazole, vinylpyrrolidone,
N-(2-methacryloyloxyethyl) ethylene urea,
N-(2-methacryloxyacetamidoethyl)-N,N'-ethyleneurea, allylalkyl
ethylene urea, N-methacrylamidomethyl urea, N-methacryoyl urea,
N-(2-methacryloyloxyethyl) ethylene urea (for example,
VISIOMER.RTM. MEEU, Evonik), 2-(1-imidazolyl) ethyl methacrylate,
N-(methacrylamido)ethyl ethylene urea (for example, Sipomer WAM II,
Rhodia) and allyl ureido wet adhesion monomer (for example, Sipomer
WAM, Rhodia). The wet adhesion monomer may be present in an amount
from 0.2% to 8.0% by weight of the total polymer.
The latex emulsion composition of this invention comprises:
i. 0-60 weight percent of a styrene-based monomer;
ii. 10 to 90 weight percent of one or more (meth)acrylic
monomers;
iii. 0-60 weight percent of a vinyl-based monomer;
iv. 0.5 to 10 weight percent of a fluorine-containing unsaturated
monomer;
v. 0.1 to 5 weight percent, of a polymerizable phosphate-functional
monomer;
vi. 0.1 to 8 weight percent of a wet adhesion monomer; all based on
the total weight of monomers.
Further, the polymer has a glass transition temperature Tg of at
least -10.degree. C. as calculated with the Fox formula and is
preferably in the range at least -10 to 35.degree. C., preferably 0
to 25.degree. C.
Latex resins based upon the invention may be successfully prepared
by conventional polymerization processes. In one embodiment, a
single stage polymerization process can be used.
In one embodiment of an all-acrylic latex emulsion copolymers, it
is preferred to add the monomer mixture, including the
fluoromonomer, to an aqueous surfactant-containing solution with
adequate stirring to obtain a stable pre-emulsion which is then
added to the polymerization reaction medium containing the acrylate
polymerization initiator and preheated to reaction temperature. The
addition of the pre-emulsion of comonomers is regulated to allow
control over the polymerization. In general, the rate of addition
of the pre-emulsion is usually such that at least one hour and
usually two hours and more are required for the total addition.
In another embodiment, the latex emulsion is prepared by two-stage
polymerization of two distinct monomer emulsions.
Conventional emulsion polymerization techniques may be used to
produce the polymer of this invention. For example, ethylenically
unsaturated monomers including the comonomer, the ionic monomer,
multi-ethylenically unsaturated monomer and the crosslinking
monomer may be emulsified with an anionic or nonionic dispersing
agent, also referred to as a surfactant, using for example from
0.05 to 10% by weight of dispersing agent based on the weight of
the total monomers. Combinations of anionic and nonionic dispersing
agents may also be used.
A polymerization initiator should be added to the polymer emulsion
composition. Exemplary initiators include, but are not limited to,
the free radical type such as t-butyl hydroperoxide, sodium
persulfate, potassium persulfate, ammonium persulfate, hydrogen
peroxide, and mixtures thereof. Initiators are generally used in
amounts of about 0.1% to 1% by weight, based on the total amount of
monomers to be copolymerized. The polymerization temperature may be
from 40-90.degree. C., and may be optimized for the initiator
system employed, as is conventional.
The coating composition of the present invention is manufactured
using techniques known to those skilled in the art of manufacturing
paint. Generally, for a waterborne composition, there are four
stages in the manufacturing process: a pre-thin stage, a grind
stage, a wash stage and a thindown stage.
In the pre-thin stage, the binder resin(s) is/are delivered to a
thindown tank, along with defoamer and chase water. Typically, a
primary binder resin and one or more secondary binder resins are
used. The primary binder resin is present in a significantly
greater amount than the secondary binder resins and is the primary
source of formula adhesion. Examples of resins useful as the
primary binder resin include acrylic latexes, vinyl acrylic
latexes, ethylene vinyl acetate latexes and other resins known to
those of ordinary skill in the art. The secondary binder resin(s)
are present in much smaller volumes and are generally added to
further enhance coating properties. Useful secondary binder
resin(s) include, but are not limited to small particle size
acrylic latexes. The binder resin(s), the chase water and defoamer
are mixed together in the thindown tank under low shear conditions
to form a pre-thin mixture.
In the grind stage, the pigments, such as calcium carbonate and dry
titanium dioxide, as well as and any other dry raw materials that
would not homogenize under low-shear mixing, are dispersed in a
mill under high shear conditions into a vehicle comprising water
and one or more dispersant(s), which may be anionic and/or
nonionic. As is known in the art, nonionic dispersants are
protective colloids that contain a hydrophilic group, such as
polyethylene oxide, and a hydrophobic group, such as a hydrocarbon
chain. Also, as is known in the art, anionic dispersants include
low molecular weight molecules like amine alcohols (such as
aminomethyl propanol), phosphate salts (such as
tetrapotassiumpyrophosphate) and polymeric compositions of
polycarboxylic acid or polycarboxylic acid copolymers. The process
of dispersing breaks up agglomerates of particles to form a better
particle distribution, and wets the particles with the vehicle.
Such wetting inhibits the reagglomeration of the pigment particles.
Examples of useful commercially available dispersants include
TAMOL.TM. 165A from Rohm & Haas and AMP-95 from Dow.
In the wash stage, water is pumped into the mill to clean the mill
and chase the grind paste into the thindown tank.
In the thindown stage, the grind paste, the chase water and the
pre-thin mixture are blended together in the thindown tank under
low shear conditions. Additional components may also be added, such
as thickeners, coalescing aids, anti-settling agents, biocides,
anti-foaming agents, freeze-thaw additives, colorants and the like.
Flow control agents may also be added to control the flow and
leveling properties of the composition. Such additional components
are generally known to those of ordinary skill in the art and
generally commercially available. For example, such additional
components may include, but are not limited to additives such as
nonionic urethane rheology modifiers, such as ACRYSOL.TM. RM
rheology modifiers from DOW as thickeners; modified ureas, such as
BYK 420 from Byk USA, or synthetic layered silicates, such as
Laponite RD from Rockwood Additives Limited, as anti-settling
agents; silicone or mineral oil type defoamers, glycols as
freeze-thaw additives, or phthalocyanaine or iron oxide dispersions
as colorants. Various types of these additives are commercially
available. Other commercially available additives include butyl
carbitol, and BIT-1,2-benzisothiazolin-3-one. Once prepared, the
coating composition concentrate is further let down with reducing
solvent, water, and generally a small amount of coalescing
solvent.
A final coating formulation typically also comprises a dispersing
aid, thickening aids, a biocide, pigments, extenders and fillers,
and a defoamer. The coating composition may contain pigment at
pigment volume concentration in the range of 0 to 85%. For example,
pigment volume concentrations in the range of 0 to 45% and 0 to 25%
are common. The pigment volume concentration of a species of
pigment particles is the percentage of the volume occupied by that
species of pigment particles, based on the total volume of the
dried coating prepared from the coating composition. Suitable
pigments include inorganic pigments, organic pigments, and fillers
such as titanium dioxide, iron oxide, zinc oxide, magnesium
silicate, calcium carbonate, organic and inorganic colored
pigments, aluminosilicates, silica, and various clays, Suitable
organic pigments also include plastic pigments such as solid bead
pigments and microsphere pigments containing voids or vesicles, and
inorganic pigments. Examples of solid bead pigments include
polystyrene and polyvinyl chloride beads.
It should be appreciated that the present invention is not limited
in any manner to the foregoing method of manufacturing the coating
composition. Other manufacturing methods may be used. For example,
a continuous paint manufacturing method utilizing component
slurries may be used to manufacture the coating composition of the
present invention.
The coating composition of this invention may be applied onto
substrates using conventional coating application methods, such as,
for example, brushing, rolling, dipping, and spraying methods.
Coating formulations of the invention have a fast dry time, early
water resistance and produce stain resistant coating films.
EXAMPLES
Table 1 shows the latex resin formulations for the latex resin of
this invention as compared to a control latex resin. The following
materials were added to a suitable reaction vessel for conventional
emulsion polymerization.
TABLE-US-00001 TABLE 1 RESIN EXAMPLES Resin Example 2 Resin Example
1 Resin of this CONTROL invention Weight % Weight % (% BOTM) (%
BOTM) Charge: Water 31.73 31.73 Water (surfactant dilute) 2.01 2.01
Anionic surfactant 0.13 (0.32) 0.13 (0.32) Aqueous Ammonia 0.02
0.02 Initial Oxidizer: Water 0.67 0.67 Ammonium persulfate 0.08
(0.20) 0.08 (0.20) Monomer Charge: Water 12.46 12.46 Anionic
surfactant 0.65 (1.58) 0.65 (1.58) Aqueous Ammonia 0.18 0.18
Methacrylic Acid 1.12 (2.72) 0.72 (1.75) HEMA Phosphate Ester --
0.72 (1.75) Monomer Wet adhesion monomer -- 1.24 (3.03)
Trifluorofunctional -- 0.78 (1.90) methacrylate Methyl Methacrylate
19.50 (47.65) 17.38 (42.47) 2-Ethylhexy1 acrylate 20.31 (49.61)
20.10 (49.10) DI Water 1.45 1.45 Oxidizer Water 3.63 3.63 Ammonium
persulfate 0.08 (0.20) 0.08 (0.20) Chase Oxidizer: Water 0.84 0.84
t-Butyl hydroperoxide 0.05 (0.08) 0.05 (0.08) Chase Reducer: Water
1.01 1.01 Isoascorbic Acid 0.02 (0.05) 0.02 (0.05) Aqueous Ammonia
0.02 0.02 Adjustment: Aqueous Ammonia 0.48 0.48 Proxel GXL 0.29
(0.19) 0.29 (0.19) Water 3.27 3.27 Weight % solids 42.01 42.01
Additional resin examples, hereinafter Resin Examples 3 through 7,
were formulated with varying amounts of fluoromonomer, phosphate
monomer and wet adhesion monomer. The resin examples were then
formulated into coating compositions as shown for Paint Examples 1
and 2 below.
Preparation of Coating Compositions
Paint Examples 1 and 2
Latex coating compositions were prepared utilizing resins prepared
in Resin Examples 1 and 2, and then included into paints made by
conventional methods known to those skilled in the art.
TABLE-US-00002 TABLE 2 PAINT EXAMPLES Paint Example 1 (Control)
Paint Example 2 Component (Weight Percent) (Weight Percent) Resin
Example 1 (Control) 32.28 -- Resin Example 2 (Resin of -- 32.28
this invention) Byk 024.sup.1 0.17 0.17 Water 13.95 13.95 Min-U-Gel
400 Clay.sup.2 0.43 0.43 Proxel BD 20.sup.3 0.09 0.09 Tamol
165A.sup.4 0.86 0.86 Strodex PK-0VOC.sup.5 0.34 0.34 Phosphate
Ester Rhodoline 697 Defoamer.sup.6 0.17 0.17 R-706 Titanium
Dioxide.sup.7 19.37 19.37 Minex 4-Nepheline Syenite.sup.8 19.11
19.11 Polymeric extender 4.73 4.73 Water 5.45 5.45 Acrysol RM-2020
NPR.sup.9 1.03 1.03 Loxanol CA 5120.sup.10 1.05 1.05 Polyphase
PW-40LV.sup.11 0.17 0.17 Sodium Omadine 0.09 0.09 Acrysol Urethan
thickener 0.02 0.02 RM-8W.sup.12 Acrysol Urethane thickener 0.38
0.38 RM-12W.sup.13 Byk 024.sup.1 0.17 0.17 Aqueous Ammonia 0.09
0.09 .sup.1BYK-024 defamer from BYK USA Inc. .sup.2Min-U-Gel 400
anti-settling agent from Active Minerals .sup.3Proxel BD 20
preservative from Lanza Microbial Control .sup.4Tamol 165A
dispersant from DOW .sup.5Strodex PK-0VOC surfactant from Ashland
Specialty Ingredients .sup.6Rhodoline 697 defoarner from Solvay
Novecare .sup.7R-706 Titanium Dioxide pigment from Chemours
.sup.8Minex-4 extender pigment from Unimin .sup.9Acrysol RM-2020
NPR rheology modifier from DOW .sup.10Loxanol CA 5120 coalescing
agent from BASF .sup.11Polyphase PW-40LV fungicide from Troy
Chemical Corporation .sup.12Acrysol RM-8W rheology modifier from
DOW .sup.13Acrysol RM-12W rheology modifier from DOW
Test Results
The washability of the coating compositions was tested by coating
Leneta panels with 7 mil wet film thickness, and ambient cured over
a 5 day period. The panels were washed for 50 cycles using a GARDCO
Washability and Wear Tester--Linear Motion Test Equipment. The
results were quantified (.DELTA.E) using an X-rite VS450
non-contact spectrophotometer--CIE L*A*B*, 6 mm aperture.
Table 3 provides a quantitative summary of washability and wear
testing results utilizing the resin formulation of Example 2 having
the phosphate monomer, and varying the fluoromonomer and the wet
adhesion monomer and then prepared as a coating composition as in
Paint Example 2. As can be seen in Table 3, the performance of the
coating in Paint Examples 2 through 7 is much improved for
washability when these monomers are employed in the coating
system.
TABLE-US-00003 TABLE 3 WASHABILITY RESULTS Resin Monomers Ex. 1
Resin Resin Resin Resin Resin Resin (% monomer wt) (Control) Ex. 2
Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 2-Ethylnexylaorylate 48.20 49.10
48.40 43.50 49.00 43.50 47.80 Methylmethaerylate 47.60 44.70 42.20
40.10 40.80 42.00 42.80 HEMA Phosphate -- 1.75 1.75 1.75 1.75 1.75
1.75 Monomer Fluorester -- 1.90 -- -- 6.30 10.00 3.90 8-FM -- --
1.30 6.20 -- -- -- Wet Adhesion -- 0.76 -- -- 0.32 0.97 2.00
Monomer (I) Wet Adhesion -- -- 0.70 1.89 -- -- Monomer (II) Results
Paint Paint Paint Paint Paint Paint Paint Ex. 1 Ex. 2 Ex. 3 Ex. 4
Ex. 5 Ex. 6 Ex. 7 .DELTA.E Mustard 8.6 0.9 1.24 0.87 1.73 1.32 1.35
.DELTA.E Crayon 7.25 2.43 3.66 2.41 0.31 0.55 0.18 .DELTA.E
Lipstick 8.64 10.7 5.33 0.78 2.45 1.21 2.04 .DELTA.E Consumer Union
4.59 0.7 3.05 1.15 0.33 0.52 0.14
* * * * *